Coral cores of massive Porites were collected to assess the frequency of flood plume events extending beyond the inshore to mid-shelf reefs. A reconstruction of the Burdekin River flow from 1648-2011 was undertaken through examining the coral luminescence as a proxy for freshwater flood plumes in the central GBR. Measurements of the luminescent lines in slices from massive Porites Skeletons, viewable under ultraviolet (UV) light act as a proxy for the frequency and intensity for effects of plume events.
The analysis was conducted on cores slices 6-7mm thick, sourced from the nearshore reefs of Havanah Island: one long (~5 m) core collected in June, 1988, and four short (<50 cm) cores collected in August, 2012; and from the mid-shore region of Britomart Reef: five short cores collected in May 2013. All core samples were taken from Porites colonies which were situated in water depths of less than 10m. Analysis included measuring luminescence intensity with AIMS’ custom-built gamma densitometer/luminometer. The luminescence range was calculated for each year, dating back from the collection of the core.
Records of daily and monthly river flow volumes for the Burdekin river, as well as rainfall records, were analysed for total annual river flow for the water year of October - September and use as a comparison of observed and reconstructed Burdekin River flow.
Coral Core IDs include:
Havanah Island: HAV01A, HAV31B, HAV32A, HAV33A, and HAV34A
Britomart Reef: BRT60A, BRT61B, BRT62B, BRT63A, and BRT64B
